This invention relates to means for applying liquid, e.g. coolant or lubricant, and in particular, although not exclusively to a spray unit for a rolling mill for supplying lubricating and/or cooling fluid to the mill rolls or to material being rolled therein.
A spray unit for a rolling mill, described in our European patent application No. 0041863, includes a spray bar, to be mounted adjacent the mill rolls, having a manifold for liquid to be sprayed and series of spray nozzles or sets of spray nozzles spaced along the spray bar. Each nozzle or set of nozzles communicates with the manifold via a conduit, and a diaphragm of a diaphragm type valve is arranged to close the end of the conduit projecting into the manifold and thereby regulate the supply of liquid, under the control of diaphragm control means. One type of diaphragm control means described in the application uses pressurised air to force the diaphragm into an obturation position. A compartment is provided adjacent each diaphragm-valve with the diaphragm defining one wall of the compartment, and the pressurised air is provided to each of the compartments to move the diaphragm to close off the end of the respective conduit. The other type of diaphragm control means described is a solenoid which is arranged so that a moveable core can engage the diaphragm to move the diaphragm to the obturation position.
While the solenoid operated diaphragm-valves can have a quicker response time than the pressure operated diaphragm-valves, and are susceptible of electronic control, the repeated engagement of the solenoid core with the diaphragm can cause undesirable wear, with a reduced working-life compared to the pressure operated diaphragm-valves. The present invention seeks to provide a spray unit for a rolling mill, which overcomes disadvantges of the described spray unit.
It is an object of the present invention to provide an improved apparatus for applying liquid for a rolling mill.
It is a further object of the invention to provide an apparatus for applying coolant to a rolling mill which is of simply and readily serviceable construction.